From 7a0a7abc52e7aad185b581481d91395e18d6c178 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sat, 13 Oct 2018 23:01:06 +0200
Subject: [PATCH] Try out a signal-like system like this:

auto* b = new Button;
b->onClick = [] (Button&) {
    printf("The button was clicked!\n");
};
---
 Widgets/Button.cpp | 3 +++
 Widgets/Button.h   | 2 ++
 Widgets/Widget.h   | 1 +
 Widgets/test.cpp   | 4 ++++
 4 files changed, 10 insertions(+)

diff --git a/Widgets/Button.cpp b/Widgets/Button.cpp
index 9313ed143b..10ec97aa50 100644
--- a/Widgets/Button.cpp
+++ b/Widgets/Button.cpp
@@ -87,5 +87,8 @@ void Button::mouseUpEvent(MouseEvent& event)
 
     update();
     Widget::mouseUpEvent(event);
+
+    if (onClick)
+        onClick(*this);
 }
 
diff --git a/Widgets/Button.h b/Widgets/Button.h
index 98c63596eb..09ad9e0458 100644
--- a/Widgets/Button.h
+++ b/Widgets/Button.h
@@ -11,6 +11,8 @@ public:
     String caption() const { return m_caption; }
     void setCaption(String&&);
 
+    std::function<void(Button&)> onClick;
+
 private:
     virtual void paintEvent(PaintEvent&) override;
     virtual void mouseDownEvent(MouseEvent&) override;
diff --git a/Widgets/Widget.h b/Widgets/Widget.h
index d592e91375..e025dc3aed 100644
--- a/Widgets/Widget.h
+++ b/Widgets/Widget.h
@@ -5,6 +5,7 @@
 #include "Rect.h"
 #include "Color.h"
 #include <AK/String.h>
+#include <functional>
 
 class Window;
 
diff --git a/Widgets/test.cpp b/Widgets/test.cpp
index dab26bb5da..5e8f403779 100644
--- a/Widgets/test.cpp
+++ b/Widgets/test.cpp
@@ -63,6 +63,10 @@ int main(int argc, char** argv)
         b->setWindowRelativeRect({ 0, 20, 100, 20 });
         b->setCaption("Button");
 
+        b->onClick = [] (Button& button) {
+            printf("Button %p clicked!\n", &button);
+        };
+
         auto* c = new CheckBox(widgetTestWindowWidget);
         c->setWindowRelativeRect({ 0, 40, 100, 20 });
         c->setCaption("CheckBox");